Under the plan, the company will go from six business units to four. It will merge two units and eliminate its McKinney, Texas-based Network Centric Systems unit, spreading the work over the remaining businesses.

As a result, Raytheon’s Space and Airborne systems unit will include Integrated Communication Systems and Advanced Programs.

The unit is based at the company's sprawling electronics facility in El Segundo, where scientists and engineers toil in underground clean rooms developing high-tech radars, sensors and cameras. The unit recorded about $6 billion in annual sales last year.

The Southland aerospace industry has been steadily downsizing to reflect new budget realities in Washington, where Congress has tightened purse strings on the Pentagon. U.S. military spending -- which grew by double digits after the Sept. 11, 2001, terrorist attacks -- is expected to decline $487 billion over the next decade.

Earlier this month, Northrop Grumman Corp. said it would close its Carson facility as part of an ongoing effort to cut costs. In November, the company revealed plans to eliminate about 200 positions in Woodland Hills and Salt Lake City.

That same month, Boeing Co. said it was trimming its executive workforce 30% from 2010 levels. It also revealed plans to sell office buildings in Seal Beach and demolish one in Huntington Beach. It has already sold property in Anaheim.

[For the record, 4 p.m. March 26: An earlier version of this post said Raytheon will go from five business units to four. Actually, it will go from six units to four by eliminating one unit and merging two others.]